Filter rods for use in the manufacture of filtered cigarettes are manufactured by filter rod making machinery such as the KDF-2 filter maker from Hauni Maschinenbau AG. In a filter maker, cellulose acetate filter plug material, referred to as tow, is drawn along a path from a source and subsequently compressed and paper wrapped in a garniture to form an elongate wrapped rod, which is cut to form individual rods. This rod forming process is well known per se to those skilled in the art.
It is also known to provide a filtered cigarette having a breakable menthol-containing capsule within the filter. The smoke from the cigarette may be selectively flavoured by squeezing the filter, thereby breaking the capsule and releasing the menthol. Thus the cigarette provides a choice as to whether to flavour the smoke with menthol or not.
Breakable capsules are conventionally incorporated into smoking article filter rods by dispensing individual capsules one by one from a delivery wheel into a flow of tow as it passes through a filter rod making machine.